Crowds across Britain have gathered on Thursday to celebrate the 90th birthday of Queen Elizabeth II, the oldest monarch in the world, who has often spoken out about her strong Christian faith and how central following Jesus Christ is in her life.
Prime Minister David Cameron called her "a rock of strength for our nation," Reuters reports. And close to 1,000 beacons will be lit later in the day to celebrate the occasion.
"All of us are here to respect the queen and to show her our affection and how much we appreciate all her years of service and to wish her a happy birthday," said Donna Werner who traveled to the queen's Windsor Castle home, west of London, all the way from Connecticut to pay her respects.
Cameron added: "Rarely has anyone in public life served for so long, served so brilliantly, worked so hard, and brought so many people together."
BBC News magazine listed on Wednesday several different reasons for why Elizabeth has been able to live such a long and productive life, noting that her Christian faith and charitable works have played a key role.
"It could be that religious faith, especially in the West, comes with a community and support network. On the other hand faith may make you feel more positive about life and death. Studies have found that optimists live longer than pessimists," said professor Sarah Harper, from the Oxford Institute of Population Ageing.
In her forward to The Servant Queen and the King She Serves, the book marking her 90th birthday, Elizabeth wrote: "I have been — and remain — very grateful to you for your prayers and to God for his steadfast love."
She added: "I have indeed seen His faithfulness."
Mark Greene, executive director of the London Institute for Contemporary Christianity, who co-authored the book, added at the time: "The Queen has served us all her adult life, with amazing consistency of character, concern for others and a clear dependence on Christ. The more I've read what she's written and talked to people who know her, the clearer that is."
Elizabeth's marriage to Prince Philip, Duke of Edinburgh, was also an important factor cited by the BBC for her longevity. The monarchs were married in November 1947 at Westminster Abbey in London, and have stayed together for 68 years.
Back in 2012 during her Diamond Jubilee celebrations, Elizabeth called Philip her "constant strength and guide."
Dickie Arbiter, her former press secretary, said, "she has a strong marriage. There has only been one man in her life and that's Philip."
Elizabeth also remains popular among the British people, with an Ipsos MORI poll last week finding that 70 percent of respondents want her to stay on as queen, while a separate BMG survey for the London Evening Standard newspaper found that 66 percent of citizens had a favorable view of her, and only 10 held a negative opinion.